Set default zoom of webview based on DPI.

Control zoom factor directly rather than using hardcoded zoom levels.

In order to ensure that the webview starts out scaled appropriately to the
current font DPI, we set default zoom level based on current DPI, e.g.:

  96 DPI - 100% zoom
  120 DPI - 125% zoom

Since this will allow zoom levels beyond the predefined set, I also change the
logic for zooming to simply add or remove 10% to the current scaling.

src/libs/browser/webcontrol.cpp

@@ -61,16 +61,6 @@ WebControl::WebControl(QWidget *parent)
 
 }
 
-int WebControl::zoomLevel() const
-{
-    return m_webView->zoomLevel();
-}
-
-void WebControl::setZoomLevel(int level)
-{
-    m_webView->setZoomLevel(level);
-}
-
 void WebControl::zoomIn()
 {
     m_webView->zoomIn();

src/libs/browser/webcontrol.h

@@ -50,9 +50,6 @@ class WebControl : public QWidget
     QWebHistory *history() const;
     void restoreHistory(const QByteArray &array);
     QByteArray saveHistory() const;
-
-    int zoomLevel() const;
-    void setZoomLevel(int level);
     void setJavaScriptEnabled(bool enabled);
 
     void setWebBridgeObject(const QString &name, QObject *object);

src/libs/browser/webview.cpp

@@ -38,59 +38,33 @@
 
 using namespace Zeal::Browser;
 
+namespace {
+const qreal MIN_ZOOM_FACTOR = 0.3;
+}
+
 WebView::WebView(QWidget *parent)
     : QWebView(parent)
 {
     page()->setNetworkAccessManager(Core::Application::instance()->networkManager());
-}
-
-int WebView::zoomLevel() const
-{
-    return m_zoomLevel;
-}
-
-void WebView::setZoomLevel(int level)
-{
-    if (level == m_zoomLevel) {
-        return;
-    }
-
-    level = qMax(0, level);
-    level = qMin(level, availableZoomLevels().size() - 1);
-
-    m_zoomLevel = level;
-
-    setZoomFactor(availableZoomLevels().at(level) / 100.0);
-    emit zoomLevelChanged();
-}
-
-const QVector<int> &WebView::availableZoomLevels()
-{
-    static const QVector<int> zoomLevels = {30, 40, 50, 67, 80, 90, 100,
-                                            110, 120, 133, 150, 170, 200,
-                                            220, 233, 250, 270, 285, 300};
-    return zoomLevels;
-}
-
-const int &WebView::defaultZoomLevel()
-{
-    static const int level = availableZoomLevels().indexOf(100);
-    return level;
+    resetZoom();
 }
 
 void WebView::zoomIn()
 {
-    setZoomLevel(m_zoomLevel + 1);
+    setZoomFactor(zoomFactor() + 0.1);
 }
 
 void WebView::zoomOut()
 {
-    setZoomLevel(m_zoomLevel - 1);
+    if (zoomFactor() <= MIN_ZOOM_FACTOR) {
+        return;
+    }
+    setZoomFactor(zoomFactor() - 0.1);
 }
 
 void WebView::resetZoom()
 {
-    setZoomLevel(defaultZoomLevel());
+    setZoomFactor(logicalDpiY() / 96.0f);
 }
 
 QWebView *WebView::createWindow(QWebPage::WebWindowType type)
@@ -291,7 +265,8 @@ void WebView::wheelEvent(QWheelEvent *event)
             delta -= 120 * direction;
         }
 
-        setZoomLevel(m_zoomLevel + levelDelta);
+        qreal newZoomFactor = zoomFactor() + levelDelta * 0.1f;
+        setZoomFactor(qMax(newZoomFactor, MIN_ZOOM_FACTOR));
         event->accept();
         return;
     }

src/libs/browser/webview.h

@@ -37,12 +37,6 @@ class WebView : public QWebView
 public:
     explicit WebView(QWidget *parent = nullptr);
 
-    int zoomLevel() const;
-    void setZoomLevel(int level);
-
-    static const QVector<int> &availableZoomLevels();
-    static const int &defaultZoomLevel();
-
 public slots:
     void zoomIn();
     void zoomOut();
@@ -65,7 +59,6 @@ public slots:
 
     QMenu *m_contextMenu = nullptr;
     QUrl m_clickedLink;
-    int m_zoomLevel = defaultZoomLevel();
 };
 
 } // namespace Browser